Synthesis and characterization of low generation poly(propyleneimine) dendrimer

Synthesis of poly(propyleneimine) dendrimer was studied. By optimizing reaction conditions, such as increasing reaction temperature and concentration of reactant, introducing a little acetic acid as catalyst and choosing ammonia/methanol as solvent, a preparative route was developed in which the poly(propyleneimine) dendrimer with relatively perfect stucture was obtained and the side reactions were suppressed to a considerable degree or even eliminated. Infrared spectrum showed that 0.5 generation poly(propyleneimine) dendrimer was obtained by reacting completely under optimum conditions, which was in favor of the growth of structure. Titration showed that 1.0 generation poly(propyleneimine) dendrimer obtained in ammonia/methanol contained 85 percent primary amine, which was better than that obtained in methanol. ¹H nuclear magnetic resonance and elementary analysis also showed that structures of low generation poly (propyleneimine) dendrimer were perfect and in accord with the expected molecu lar structure.